초록
<P><B>Abstract</B></P><P>In this study, <I>Saccharomyces cerevisiae</I> was genetically engineered to harbor the capability of utilizing celluloses for bioethanol production by displaying active cellulolytic enzymes on the cell surface. An endo‐1,4‐β‐glucanase gene <I>egX</I> was cloned from <I>Bacillus pumilus</I> C‐9 and its expression products, the EGX cellulases, were displayed on the cell surface of <I>S. cerevisiae</I> by fusing <I>egX</I> with <I>aga2</I> that encodes the binding subunit of the <I>S. cerevisiae</I> cell wall protein α‐agglutinin. To achieve high gene copies and stability, multicopy integration was obtained by integrating the fusion <I>aga2</I>‐<I>egX</I> gene into the rDNA region of the <I>S. cerevisiae</I> chromosome. To achieve high expression and surface display efficiency, the <I>aga2</I>‐<I>egX</I> gene was expressed under the control of a strong promoter. The presence of the enzymatically active cellulase fusion proteins on the <I>S. cerevisiae</I> cell surface was verified by carboxymethyl cellulase activity assay and immunofluorescence microscopy. This work presented a promising strategy to genetically engineer yeasts to perform efficient fermentation of cellulosic materials for bioethanol production.</P>